In signing this treaty, we know that it will not be any of us here today that will reap the greatest benefits of it. Rather, we hope that our successors, our descendants, shall keep it alive and, through genuine good will and cooperation, build a lasting friendship between the peoples of the Ethereal Demesnes and the Chiss Ascendancy.
—Kolnstark, Vaderonian Chairman of the Diet who was one of the Ethereal-Chiss Treaty's original signatories
The Ethereal-Chiss Treaty, also known as the Ethereal Demesnes-Chiss Ascendancy Treaty or shortened to the Demesnes-Ascendancy Treaty, was a treaty establishing full diplomatic relations between the Ethereal Demesnes and the Chiss Ascendancy, which were, for thousands of years, arguably the two strongest powers in the Unknown Regions. The treaty was initially signed at uncertain date prior to either the Demesnes or the Ascendancy conducting true first contact with the original Galactic Republic, and was later revised millennia later following the Ethereal experiences in the Hollow Campaign and Chiss experiences in the Swarm War.
The original version of the Ethereal-Chiss Treaty was succinct, leaving little to the imagination about its terms and being highly specific and limited in its scope, largely owing to Chiss lack of trust towards the perceived unknown aliens of the Demesnes and Ethereal uncertainties about the long-term goals and viability of the Ascendancy as a political entity. Nevertheless, the two sides negotiated and signed the treaty in good faith, establishing full and open diplomatic and trade relations, including the full charting and long-term joint maintenance of the Ancient Demesnes Path to connect the two astrographically, a limited degree of joint exploration and knowledge sharing regarding the Unknown Regions and Wild Space, cooperation in combating piracy and marauding in the Unknown Regions and Wild Space, and joint colonization and administration of Estiron, which would become the seat of the Chiss-Ethereal Diplomatic Legation.
Estiron was a previously-uninhabited world within the political and astrographical boundaries of the Ethereal Demesnes, selected there rather than between the two powers as a sign of trust and good faith towards the Ascendancy by the Demesnes, and a willingness by the Ethereal government to win Chiss trust in the long-term by placing themselves at greater risk than the Ascendancy and accepting responsibility for the safety and livelihood of the Chiss colonists.
Following Ethereal victory in the Hollow Campaign, the Ethereal government voted in favor of revising both the Ethereal-Chiss Treaty and the Ethereal-Jedi Treaty. Under the supervision of Ethereal Empress Atheria Valdayn and Aristocra Tol'adrel'csapla, the treaty was expanded to include articles and clauses first continuing prior terms, then adding on to them with exploration of further shared colonial initiatives, full cooperation and sharing of information regarding interstellar exploration, a full and public military alliance limited to the Unknown Regions and Wild Space, the establishment of a joint scientific and engineering committee to develop technologies together, and a secret clause establishing cooperation in analysis and management of extra-galactic and Unknown Regions threats and bringing the Ascendancy into the Demesnes' Slipspace Hyperdrive development program.
As a result of the treaty's revision, the Ascendancy and Demesnes established several more joint colonies, including at least Colonial Station Ari'to, Csarind, and Pelnuto. The Demesne Defense Forces (and extended Ethereal Military) and Chiss Expansionary Defense Force also began conducting joint drills, fleet movements, and a limited number of combat operations. Several technological achievements emerged following the treaty's revision, as well, including the Plasma Maser and Plasma Megamaser weapons, the Ascendancy-class star cruiser, and the Alliance Citadel space station. Activity along the Ancient Demesnes Path hyperspace route increased around this time, and, following the Demesnes' successful development and deployment of the Slipspace Hyperdrive, information regarding conditions and celestial objects outside the galaxy was shared by the Demesnes with the Ascendancy.